<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        html, body {
            margin: 0;
            height: 100%;
        }

        canvas {
            display: block;
        }
    </style>
</head>

<body onload="draw();">
</body>
<script src="https://cdn.bootcss.com/three.js/91/three.min.js"></script>
<script src="js/libs/inflate.min.js"></script>
<script src="js/FBXLoader.js"></script>
<script src="js/controls/OrbitControls.js"></script>
<script src="js/libs/stats.min.js"></script>
<script src="https://cdn.bootcss.com/dat-gui/0.7.1/dat.gui.min.js"></script>
<script src="js/Detector.js"></script>

<script>
    var renderer, camera, scene, gui, light, stats, controls, meshHelper, mixer, action;
    var clock = new THREE.Clock();

    function initRender() {
        renderer = new THREE.WebGLRenderer({antialias: true});
        renderer.setPixelRatio(window.devicePixelRatio);
        renderer.setSize(window.innerWidth, window.innerHeight);
        renderer.setClearColor(0xeeeeee);
        renderer.shadowMap.enabled = true;
        //告诉渲染器需要阴影效果
        document.body.appendChild(renderer.domElement);
    }

    function initCamera() {
        camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 2000);
        camera.position.set(100, 200, 300 );
    }

    function initScene() {
        scene = new THREE.Scene();
        scene.background = new THREE.Color( 0xa0a0a0 );
        scene.fog = new THREE.Fog( 0xa0a0a0, 200, 1000 );
    }

    //初始化dat.GUI简化试验流程
    function initGui() {
        //声明一个保存需求修改的相关数据的对象
        gui = {
            animation: true,
            helper:true //模型辅助线
        };
        var datGui = new dat.GUI();
        //将设置属性添加到gui当中，gui.add(对象，属性，最小值，最大值）
        datGui.add(gui, "animation").onChange(function (e) {
            if (e) {
                action.play();
            }
            else {
                action.stop();
            }
        });

        datGui.add(gui, "helper").onChange(function (e) {
            meshHelper.visible = e;
        })
    }

    function initLight() {
        scene.add(new THREE.AmbientLight(0x444444));

        light = new THREE.DirectionalLight(0xffffff);
        light.position.set(0, 200, 100 );

        light.castShadow = true;
        light.shadow.camera.top = 180;
        light.shadow.camera.bottom = -100;
        light.shadow.camera.left = -120;
        light.shadow.camera.right = 120;

        //告诉平行光需要开启阴影投射
        light.castShadow = true;

        scene.add(light);
    }

    function initModel() {

        //辅助工具
        var helper = new THREE.AxesHelper(50);
        scene.add(helper);

        // 地板
        var mesh = new THREE.Mesh( new THREE.PlaneBufferGeometry( 2000, 2000 ), new THREE.MeshPhongMaterial( { color: 0xffffff, depthWrite: false } ) );
        mesh.rotation.x = - Math.PI / 2;
        mesh.receiveShadow = true;
        scene.add( mesh );

        //添加地板割线
        var grid = new THREE.GridHelper( 2000, 20, 0x000000, 0x000000 );
        grid.material.opacity = 0.2;
        grid.material.transparent = true;
        scene.add( grid );

        //加载模型
        var loader = new THREE.FBXLoader();
        loader.load("json/Samba Dancing.fbx", function (mesh) {

            console.log(mesh);

            //添加骨骼辅助
            meshHelper = new THREE.SkeletonHelper(mesh);
            scene.add(meshHelper);

            //设置模型的每个部位都可以投影
            mesh.traverse( function ( child ) {
                if ( child.isMesh ) {
                    child.castShadow = true;
                    child.receiveShadow = true;
                }
            } );

            //AnimationMixer是场景中特定对象的动画播放器。当场景中的多个对象独立动画时，可以为每个对象使用一个AnimationMixer
            mixer = mesh.mixer = new THREE.AnimationMixer(mesh);

            //mixer.clipAction 返回一个可以控制动画的AnimationAction对象  参数需要一个AnimationClip 对象
            //AnimationAction.setDuration 设置一个循环所需要的时间，当前设置了一秒
            //告诉AnimationAction启动该动作
            action = mixer.clipAction(mesh.animations[0]);
            action.play();

            scene.add(mesh);
        });
    }

    //初始化性能插件
    function initStats() {
        stats = new Stats();
        document.body.appendChild(stats.dom);
    }

    function initControls() {

        controls = new THREE.OrbitControls(camera, renderer.domElement);
        //设置控制器的中心点
        controls.target.set( 0, 100, 0 );
        // 如果使用animate方法时，将此函数删除
        //controls.addEventListener( 'change', render );
        // 使动画循环使用时阻尼或自转 意思是否有惯性
        controls.enableDamping = true;
        //动态阻尼系数 就是鼠标拖拽旋转灵敏度
        //controls.dampingFactor = 0.25;
        //是否可以缩放
        controls.enableZoom = true;
        //是否自动旋转
        controls.autoRotate = false;
        controls.autoRotateSpeed = 0.5;
        //设置相机距离原点的最远距离
        controls.minDistance = 1;
        //设置相机距离原点的最远距离
        controls.maxDistance = 2000;
        //是否开启右键拖拽
        controls.enablePan = true;
    }

    function render() {

        var time = clock.getDelta();
        if (mixer) {
            mixer.update(time);
        }

        controls.update();
    }

    //窗口变动触发的函数
    function onWindowResize() {

        camera.aspect = window.innerWidth / window.innerHeight;
        camera.updateProjectionMatrix();
        renderer.setSize(window.innerWidth, window.innerHeight);

    }

    function animate() {
        //更新控制器
        render();

        //更新性能插件
        stats.update();

        renderer.render(scene, camera);

        requestAnimationFrame(animate);
    }

    function draw() {
        //兼容性判断
        if (!Detector.webgl) Detector.addGetWebGLMessage();

        initGui();
        initRender();
        initScene();
        initCamera();
        initLight();
        initModel();
        initControls();
        initStats();

        animate();
        window.onresize = onWindowResize;
    }


</script>
</html>